 Hello and welcome to NewsClick. Today we are back again with Professor Satyajit Rath discussing COVID-19 and what state the pandemic is currently in in India and in other parts of the world. So then looking at what the government of India is saying that in 100 odd districts now only out of 600 odd districts, we have positivity ratio around 10 percent or below which would seem to indicate that at least on one metric the pandemic seems to now restricted to only some parts of the country and other parts slowly going down as well hopefully in these parts also the numbers would start to fall if they are not already falling. So can we say at least in India that Omicron wave is now on the way in? Well certainly at the nationwide level total case counts have been steadily falling now for days if not weeks and as you point out test positivity rates have been falling in a fairly large number of districts. So by and large the interpretation that the explosive growth of case numbers in local areas particularly metropolitan areas is now over and those numbers are falling and in smaller more rural district communities and populations the rate of growth of case numbers is not so much as to lead to this adding numbers to a nationwide count up search. So in that sense yes and this is very much reflective of what's happening in the world. So what we see is a so sharp vertical rise because of urban areas going up very quickly then rapid fall but not falling at that speed because now other clusters dispersed areas remote areas all add to the tail and therefore you see a fall of tail which is not as rapid as a rise but nevertheless a fall this is replicated most countries in the world as well except maybe for those countries which started the wave a little late. Well you know let me give you two examples one from the global north and one from the global south that underlined the point that we keep discussing in these conversations about the local spread issues. So across the European Union as a whole case numbers and test positivity rates are both apparently stable or falling but that's an average across the European Union. Case numbers are still rising in Germany for example test positivity rates are rising not simply in Germany but also in France in Austria and so on and so forth. So there are local realities lived local realities that are different from approximations and averages across large political formations. Let me give you an example from the global south case numbers test positivity rates in Argentina have been if my memory serves correctly have been falling but right next door well okay across the Andes but right next door in Chile both case numbers and test positivity rates are still on the rise. So both of these examples I'm suggesting underline the fact that different local conditions tend to drive different trajectories of Omicron case rises both when they will start how rapidly they will rise and how soon they will fall and that distributed diverse situation continues to be our reality. Nonetheless on a global average sure the case numbers globally in the Omicron search have been falling they've been falling in the United States for example but even today US numbers on a per million population basis are extraordinarily high and they are not evenly distributed across communities in the United States. Some states some neighborhoods are bearing a disproportionate front whereas others are not. Interestingly enough China which had followed the very different trajectory of having no cases at all if they could handle it now seems to be facing a test in Hong Kong but even if we take Hong Kong for instance they're really paranoid over the fact they've got 1200 infections in a city population urban population that large which in any other part of the world would have been taken as a case not only not to worry about being relieved it's only 1200. So it's a very different response we are seeing in China than we are seeing in any other part of the world. Absolutely and again to go from the specific to the more general one of the things that this phase of the pandemic the last two three months of the pandemic have underlined for us is the growing divergence between considering case numbers as identified by detection of virus and severe illness numbers as identified where evidence is available where numbers are available from hospitalization numbers and where those are not available which is across much of the global south certainly at least from confirmed death numbers. These numbers are now beginning to diverge in 2020 and through much of 2021 as case numbers rose as virus positive numbers rose hospitalizations and deaths also rose but in the last three months of the micron fuel rise in case numbers hospitalizations and deaths have not grown at the same rate that case numbers have grown and that is an indication of two or three things one it is an indication that the pandemic is on the on the retreat as far as its effects on communities is concerned but the second is that we are detecting case numbers based on case sampling that has varied through 2020, 2021, 2022 that varies between different places we have not been doing an independent stable denominator for test positivity which is simply community sampling in local areas. If we have been doing that then the test positivity rate over time would have been comparable and would have been a far more reliable measure of pandemic spread both locally and more broadly since we haven't been doing that the test positivity rate is really just a predictor for what's likely to happen in that area over the next fortnight or so. Yeah indication of what I call in my term slope of the graph rather than actually what is happening so we are detecting the slope it's going up or it's going down but the actual numbers don't mean that much as the direction at which it is going. This brings me to this question of what has been troubling us of course where did this Omicron come from suddenly and because it seems to have suddenly caught fire and proceeded to the pace we haven't seen the rate of infections the ability to infect from one to the family for example is much higher than what we saw earlier of course saving grace the due to our earlier immunity vaccine infection whatever it might be that the effect has been less or the Omicron variant itself has been less dangerous to our system but when did it come from still a very important question because there have been various hypothesis three major hypothesis we have discussed this earlier in a remote compromised person or in an isolated population or going to a animal population and coming back again so any evidence now of which of this hypothesis is likely to be correct or some actual discussions about it. There is a paper that is making the rounds from the Chinese Academy of Sciences in Beijing that's published in a scientific journal so this is not a preprieve it's published in the journal Genetics and Genomics and that paper uses sequence information viral genetic sequence information and as we've discussed the sequence information allows collection of sequences into closely linked lineages allows building family trees of descent of various virus isolates and so on and so forth. This is the next strain kind of genetic trees that we are talking about and so a couple of issues arise from that analytical approach it's a little unclear just how robust and reliable that analysis is but as a matter of interest it makes two or three points the first point it makes is that the spike protein changes in the Omicron lineages seem to have been very specifically selected seem to have been under evolutionary selection pressure and that selection pressure seems to have gone in two different it seems to have two different components one seems to be an actual evading the immune response to the pre-existing strains of the virus which is interesting because as we've said over the past two years it's when vaccination worldwide becomes quite extensive that the pressure of vaccination on the virus population to lead to the emergence of a vaccine resistant strain at least in terms of infection and spreading not so much in terms of illness will be developed and that seems to be at least a component in the emergence of the Omicron strain but the other thing that this analysis from the Chinese Academy of Sciences has thrown up is that the alterations in the Omicron sequence particularly in the spike protein seem to be similar in structural terms with alterations that would be expected if the virus was getting used to rodents to mice to as hosts so the authors actually propose that it's at least plausible that the Omicron lineage may be an example of a situation where some mutation in humans allowed the virus to transfer to mice and then it sort of grew in underwent modifications in the mice and then it happened to come back into humans I'm not suggesting that this is necessarily what happened but I think that it is important and interesting for us to keep this in mind as part of a larger concern and the larger concern is we need to keep in mind that we've always known that SARS-CoV-2 or as people have begun referring to it HSCV-2 human SARS-CoV-2 so HSCV-2 can infect other non-human host species we know they could infect mink which are members of the weasel family we've known they could infect hamsters members of the rodent family we've known they could infect cats and lions and leopards in zoos which are members of the cat family we've known that they could infect in the US wild populations of white-tailed deer which are members of a whole different deer family ungulate family altogether so clearly the family and suddenly the bad family is very much relevant in the picture so there are a half a dozen families of a million origin which can serve as reservoirs for SARS-CoV-2 to expand to be selected to be available as a diverse population to grow exactly like members of the influenza virus family which grow in birds which grow in pigs which grow in you know and it it's when infectious viruses can have multiple host species that achieving eradication becomes next to impossible number one and number two even more specifically constant vigilance monitoring careful sequencing careful identification in location and in time and a public health spirited development of appropriate vaccines becomes an absolutely necessary component of the public health response globally and that is what is underlined by this recent paper that's a very interesting point you're making because a of course that there have been speculations of how this virus has suddenly emerged after a long break as it appears to be in the lineages that were observed suddenly it appeared out of nowhere and therefore the one of the postulates of course has been animal reservoir and initial river zoos and then again back to human population as it normally is but the fact that what you're saying is that this is something that we have to take note of in terms of the public health system being vigilant about it globally as well as of course nationally and that is something we have now to consider when you talk of SARS-CoV-2 that that we have to add to the influenza because as we know influenza has always been hovering on the wings literally on the wings as something which can come back in a very very disastrous way particularly with one kind of avian flu which still is not spreading among the human population but some minor tweak somewhere could make that happen therefore this is something that we have to take into account Satyajit thanks for talking to us leading us through the rather difficult labyrinth that the pandemic has been both scientifically and in public health terms and yes I think we need to talk about the vaccines can we have universal vaccines for both flu as well as SARS-CoV-2 like infections and of course what kind of vigilance we have to exercise it's not simply national health vigilance but it has to be a global health vigilance and how we can do that thank you very much Satyajit for being with us and explaining to us through all the ramifications of the COVID-19 pandemic and we'll see you again next week this is all the time we have this week for COVID-19 discussions and we'll be back next week with some more discussions on this again